Balancer for washing machine and method of manufacturing the same

ABSTRACT

A balancer for a washing machine includes a housing into which a fluid is injected, in which the housing is integrally formed by blow molding.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority to Korean Patent Application No. 10-2014-0088820, filed on Jul. 15, 2014, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

Embodiments according to the present disclosure relate to a balancer for a washing machine and a method of manufacturing the same, and more particularly, to a balancer for a washing machine, and a method of manufacturing the same, which prevents vibration and noise by maintaining a dynamic balance of the rotary tub in the washing machine.

BACKGROUND

In general, as illustrated in FIG. 1, a washing machine washes laundry by rotating a rotary tub 2, which holds the laundry, using a drive motor 3. The rotary tub 2 is rotated at a low speed in forward and reverse directions during washing, and the rotary tub 2 is rotated at high speed in the forward direction during spin-drying.

If the rotary tub 2 is rotated at high speed during spin-drying and if the laundry is not uniformly distributed in the rotary tub 2 but instead collects in a region of the tub, then the center of gravity and the center of rotation of the rotary tub 2 do not match, resulting in vibration and noise. If this phenomenon is repeated, components (which include the rotary tub 2, a rotation shaft, the drive motor 3, and the like) can break down or their life span may be shortened.

In particular, a drum type washing machine has a structure in which a rotary tub for holding laundry is disposed horizontally, and the rotary tub is rotated at high speed during spin-drying during which laundry may collect unevenly at the bottom of the rotary tub due to gravity, and as a result, the center of gravity and the center of rotation do not match each other, such that there is a high possibility that vibration and noise will occur.

Therefore, a balancer 1, which serves to maintain dynamic balance of the rotary tub 2, is typically installed in the drum type of washing machine, and also in a vertical axis type of washing machine in which the rotary tub 2 is installed vertically.

Referring to FIG. 2, the balancer 1 for a washing machine in the related art includes an upper housing 10 and a lower housing 20 that are manufactured by general injection molding, then by filling the lower housing 20 with a fluid such as salt water and fusing the upper housing 10 with an upper end of the lower housing 20.

Otherwise, the balancer 1 is manufactured in a way in which the upper housing 10 and the lower housing 20 are fused together, then an internal space between the upper housing 10 and the lower housing 20 is filled with a fluid such as salt water through a fluid inlet 32 formed in the upper housing 10, and then a sealing cap 30 is fused with the fluid inlet 32.

However, because the balancer 1 for a washing machine in the related art has a structure in which the upper housing 10 and the lower housing 20 are manufactured by general injection molding and then fused together, and also may have a structure in which the fluid inlet 32 formed in the upper housing 10 and the sealing cap 30 are fused together, molds for the upper housing 10 and the lower housing 20 need to be separately manufactured. This can be problematic because it takes a long time to manufacture the molds, and therefore the cost of manufacturing the molds and the unit price of the balancer 1 are increased.

There is also a problem in that fusion debris, which is produced when the operation of fusing the respective components is performed, enters the interior of the upper housing 10 and the lower housing 20 and hinders movement of the fluid such as salt water, which causes vibration and noise. There is also another problem in that the fusion debris, once it enters the interior of the upper housing 10 and the lower housing 20, degrades the exterior of the balancer 1, and can interfere with any structure that is coupled to the rotary tub.

Korean Patent Application Laid-Open No. 10-2007-0115284 (published on Dec. 6, 2007) is an example of the related art.

SUMMARY

Embodiments according the present disclosure provide a balancer for a washing machine, where the balancer is integrally formed using blow molding, and a method of manufacturing the balancer.

A technical problem solved by the present invention is not limited to the aforementioned technical problems, and any other not-mentioned technical problem will be obviously understood from the description below by those skilled in the technical field to which the present disclosure pertains.

An embodiment according to the present disclosure provides a balancer for a washing machine. The balancer is coupled to a rotary tub of the washing machine, and includes a housing into which a fluid is injected, where the housing is integrally formed by blow molding.

The balancer may further include: at least one inlet which is formed in a surface of the housing; and a sealing cap which seals the inlet, where the sealing cap is inserted into the inlet and fused with the inlet.

In an embodiment, the inlet is also a passage for air that is injected into the housing when the blow molding of the housing is performed.

In an embodiment, the balancer includes a plurality of coupling members that are provided along a circumference of the housing. Each coupling member has a coupling hole for coupling the housing to the rotary tub. The blow molding of the housing is performed after the plurality of coupling members are inserted into the mold.

In another embodiment according to the present disclosure, a method of manufacturing a balancer for a washing machine includes a blow molding step of integrally forming a housing for the balancer into which a fluid (e.g., salt water) is injected.

In an embodiment, the method further includes: a fluid injection step of injecting the fluid into the balancer through at least one inlet formed in a surface of the housing; and a sealing cap fusion step of inserting a sealing cap into the inlet, and fusing the sealing cap with the inlet.

The inlet may also be a passage for air that is injected into the housing in the blow molding step.

In an embodiment, the method further includes an insertion step of inserting a plurality of coupling members into a mold for blow molding prior to the blow molding step, in which the coupling members are provided along a circumference of the housing, and have coupling holes for coupling the housing to the rotary tub.

According to the present disclosure, the balancer for a washing machine is integrally formed such that the mold for manufacturing the housing may be simplified, thereby shortening the period of time required to manufacture the mold, and reducing the cost of manufacturing the mold and the unit price of the balancer.

The balancer for a washing machine is integrally formed, such that fusion debris is prevented from being produced, and a fluid such as salt water smoothly flows in the balancer, thereby preventing the occurrence of vibration and noise.

Fusion debris is prevented from flowing external to the balancer, thereby allowing the exterior of the balancer to have a structure that can be smoothly coupled to the rotary tub of the washing machine.

A portion of the balancer, which has a structure that is not suitable for blow molding, is manufactured by general injection molding, and inserted into the mold first, and then the blow molding may be performed to form the balancer.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a conventional washing machine.

FIG. 2 is an exploded perspective view illustrating a balancer in a conventional washing machine.

FIGS. 3 and 4 are cross-sectional views of a mold used in a process of manufacturing a balancer for a washing machine in an embodiment according to the present disclosure.

FIGS. 5 and 6 are perspective views illustrating a balancer for a washing machine in embodiments according to the present disclosure.

FIG. 7 is a flowchart illustrating an example of a method of manufacturing a balancer for a washing machine in an embodiment according to the present disclosure.

DETAILED DESCRIPTION

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. In this description, sizes or shapes of constituent elements illustrated in the drawings may be exaggerated for clarity and ease of description. The terms used in the description, which are specially defined in consideration of configurations and operations according to the present disclosure, may vary depending on the intention or usual practice by a user or an operator. The scope and spirit of the present disclosure is not limited to the suggested embodiments. Those skilled in the art who understand the scope and spirit of the present disclosure may easily carry out other embodiments within the scope and spirit of the present disclosure, and of course, those embodiments also belong to the scope and spirit of the present disclosure.

FIGS. 3 and 4 are cross-sectional views of a mold used in a process of manufacturing a balancer for a washing machine in an embodiment according to the present disclosure, and FIGS. 5 and 6 are perspective views illustrating a balancer for a washing machine in embodiments according to the present disclosure. An example configuration and structure and the like of a balancer for a washing machine will be described in detail with reference to FIGS. 3 to 6.

The balancer is coupled to a rotary tub of a washing machine to maintain a dynamic balance of the rotary tub, and includes a housing 110, a sealing cap 120, coupling members 130, and the like.

The housing 110 defines the overall external appearance of the balancer, and the interior of the housing 110 is filled with a fluid such as salt water.

Referring to FIGS. 3 and 4, in embodiments according to the present disclosure, the housing 110 is integrally formed by blow molding. Specifically, blow molding is a molding technology for forming a hollow plastic molded product. For example, the housing 110 can be manufactured by heating an intermediate molded product, which is called a preform 113, to an appropriate temperature, and thereafter injecting air into a mold 102 using a stretch rod 114 so that the preform conforms to the walls of the mold and takes the shape of the mold. The air is injected into the mold 102 through inlets 112 that are spaced at intervals along the upper surface of the mold and the resulting housing 110.

When the housing 110 is integrally formed by blow molding as described above, the mold 102 can be simply formed as a single piece, thereby shortening the period of time required to manufacture the mold 102, and therefore reducing the cost of manufacturing the mold 102 and the unit price of the balancer.

A fusion process is omitted when the housing 110 is manufactured as just described, such that fusion debris is prevented from being produced. As a result, the fluid F, such as salt water, flows smoothly in the balancer, thereby preventing vibration and noise from occurring.

The sealing cap 120 seals at least one inlet 112 formed in a surface of the housing 110.

Referring to FIGS. 5 and 6, the inlets 112 are at predetermined intervals along a circumference of the upper surface of the housing 110, and the fluid F (such as salt water) is injected into the housing 110 through the inlets 112.

After the fluid F is injected into the housing 110, a sealing cap 120 is inserted into each inlet 112 and then fused with the inlet 112 so as to seal the interior of the housing 110. Here, as illustrated in FIG. 4 and as mentioned above, the inlets 112 are also passages for air that is injected into the housing 110 when blow molding of the housing 110 is performed.

As illustrated in FIGS. 5 and 6, a plurality of coupling members 130 are provided at predetermined intervals along a circumference of the housing 110. The coupling members 130 have coupling holes 132 for coupling the housing 110 to the rotary tub of the washing machine. That is, the balancer is coupled to the rotary tub by members such as bolts or screws that penetrate the rotary tub into the coupling holes 132.

As illustrated in FIGS. 3 and 4, the coupling holes 132 allow the inside and outside portions of the housing 110 to communicate with each other, such that the coupling members 130 are inserted into the mold 102 prior to the blow molding of the housing 110, and the blow molding of the housing 110 is performed with this configuration.

That is, a coupling hole 132, which penetrates the inside and outside portions of the housing 110, is formed in the coupling member 130, and air injected into the housing 110 would be discharged to the outside through the coupling holes 132 when blow molding is performed, in which case the housing 110 including the coupling holes 132 is not suitable to be manufactured by blow molding. Therefore, the housing 110 is manufactured by inserting the coupling member 130 including the coupling holes 132 into the mold 102 first (before blow molding), and then blow molding of the remaining portion is performed.

Therefore, a portion of the balancer is manufactured by general injection molding, that portion is then inserted into the mold, and then blow molding is performed to form the remainder of the balancer.

Fusion debris is prevented from being produced because blow molding eliminates the need for the fusion process that was previously described herein. Consequently, fusion debris and the like are not caught in the coupling hole 132 and, as a result, the balancer has a structure that is smoothly coupled to the rotary tub.

FIG. 7 is a flowchart illustrating a method of manufacturing the balancer for a washing machine in an embodiment according to the present disclosure. The method of manufacturing the balancer will be described in detail with reference to FIG. 7.

The method of manufacturing the balancer includes an insertion step S130, a blow molding step S110, a fluid injection step S112, a sealing cap fusion step S120, and the like in order to integrally form the housing 110.

In the insertion step S130, before the housing 110 is integrally formed using blow molding, the plurality of coupling members 130 is inserted into the mold 102 that will subsequently be used for the blow molding (at the circumference of the mold as shown if FIG. 3, for example).

That is, as described above, since the coupling members 130 are provided along the circumference of the housing 110, and the coupling holes 132 for coupling the housing 110 to the rotary tub of the washing machine are formed in the coupling member 130, then air injected into the housing 110 would be discharged to the outside through the coupling holes 132 when blow molding is performed, such that the housing 110 with the coupling holes 132 is not suitable to be manufactured by blow molding.

Therefore, to address this, the housing 110 is manufactured by inserting the coupling members 130 with the coupling holes 132 into the mold 102 first in the insertion step S130, and then performing the blow molding of the remaining portion.

In the blow molding step S110, the housing 110 into which the fluid F, such as salt water, will be injected is integrally formed inside the mold by blow molding in a configuration in which the coupling members 130 were previously inserted into the mold 102 as described above. The housing 110 is formed as a single piece that conforms to the mold 102 and that integrally incorporates the coupling members 130.

In the fluid injection step S112, the fluid F, such as salt water, is injected into the balancer through the inlet 112, which is also a passage for the air that was injected into the housing 110 in the blow molding step S110.

In the sealing cap fusion step S120, after the fluid F is injected into the housing 110, the sealing cap 120, which seals the inlet 112, is inserted into the fluid inlet 112 and fused with the inlet 112.

From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims. 

What is claimed is:
 1. A balancer for a washing machine, the balancer coupled to a rotary tub of the washing machine, the balancer comprising: a housing into which a fluid is injected, wherein the housing is integrally formed by blow molding.
 2. The balancer of claim 1, further comprising: at least one inlet which is formed in a surface of the housing; and a sealing cap which seals the inlet, wherein the sealing cap is inserted into the inlet and fused with the inlet.
 3. The balancer of claim 2, wherein the inlet is also a passage for air that is injected into the housing when the blow molding of the housing is performed.
 4. The balancer of claim 1, further comprising: a plurality of coupling members along a circumference of the housing, having coupling holes formed therein for coupling the housing to the rotary tub, wherein the blow molding of the housing is performed after the plurality of coupling members is inserted into the mold for blow molding.
 5. A method of manufacturing a balancer for a washing machine, the balancer coupled to a rotary tub of the washing machine, the method comprising: integrally forming, by blow molding, a housing into which a fluid is injected inside the balancer.
 6. The method of claim 5, further comprising: injecting the fluid into the balancer through at least one inlet formed in a surface of the housing; inserting a sealing cap into the inlet; and fusing the sealing cap with the inlet.
 7. The method of claim 6, wherein the inlet is also a passage for air that is injected into the housing in the blow molding step.
 8. The method of claim 5, further comprising: inserting a plurality of coupling members into a mold for blow molding prior to the blow molding step, wherein the coupling members are provided along a circumference of the housing, and have coupling holes formed therein for coupling the housing to the rotary tub.
 9. A method of manufacturing a balancer for a washing machine, the method comprising: inserting a plurality of coupling members into a mold at the circumference of the mold; and after inserting the coupling members into the mold, using blow molding to form a housing for the balancer as a single piece that conforms to the mold and that integrally incorporates the coupling members.
 10. The method of claim 9, further comprising: after the blow molding is completed, injecting a fluid into the balancer through an inlet in the housing.
 11. The method of claim 10, further comprising: inserting a sealing cap into the inlet; and fusing the sealing cap with the inlet to seal the inlet.
 12. The method of claim 10, wherein the inlet is also a passage for air that is injected into the housing in the blow molding.
 13. A washing machine comprising the balancer of claim 9, the washing machine further comprising a rotary tub coupled to the balancer via members inserted into holes in the coupling members. 